If you like violence, Rap, or a combination then this is definitely your game!
You start off pummeling small timers in an unknown underground fighting club called the foundation. These small timers work for D-Mob's greatest rival Crow(Snoop Dogg). And gradually you build up your fighter's skills and rep and become the greatest fighter of all time etc. But I'll try not to spoil too much. Basically you can edit 2 main things, your skills and your appearance. For your skills you go to the Gym owned by Henry Rollins. You can increase your skills, which are speed, upper strength,lower strength, health and toughness. Other things you can access from the Gym are Blazin' Moves which you use to completely mash up or KO your opponents, or you can add more fighting styles to your arsenal, you can have three in total, including the fighting style you started with. The fighting styles consist of Street Fighting, Kickboxing, Martial Arts, Wrestling and Submissions. However when you purchase a new fighting style you cannot choose to switch between them, they blend together. Now for appearance, there are several stores which take cash rather than development points. There is a barbershop, a tattoo shop owned than none other than Manny, a jewelry store and a clothes shop owned by D-Mobb's failure Snowman. All of these put up your reputation when purchased. But if you want the most rep your gonna have to turn those pockets inside-out. But trust me, its worth it.
In exhibition you choose a style of many marvellous matches, including a subway match, and a window match. And you can guess what the objective of those matches is. You choose your fighters, which are unlocked in Story mode or with points earned from completing exhibition matches. Most characters are unlocked from story mode, but there are a few that can only be earned through continous exhibitions, such as the shop owners. Which can be a bit of a slog unless of course you hookup with some friends for some outrageous multiplayer action!
All in all, Def Jam is one truly amazing game, and anyone that doesn't like it has serious issues.